There are mainly two types of existing screen changers of an extruder, i.e., a manual screen changer and a hydraulic pull-type screen changer. The manual screen changer is operated by first shutting down the extruder and then taking out a filter screen in the screen changer for change. However, the hydraulic pull-type screen changer is operated by pushing and pulling the filter screen left and right for change. When the filter screen is changed, the extrusion materials on the extruder are interrupted, causing interruption of continuous production, which directly affects normal production of the extruder, and meanwhile also produces a certain amount of waste materials. Therefore, the foregoing two types of existing screen changers of the extruder mainly have the following shortcomings: during change of filter screens, manual intervention is required, automation cannot be achieved, and it takes time, efforts and materials; moreover, the production process will be interrupted, the efficiency of production is directly affected, and there is a possibility of air entering the material, reducing the quality of a product.